Heskey has been revitalised since his former Liverpool boss Houllier took charge at Villa Park three months ago. He had scored three goals in six games before suffering a knee injury and added to that tally in his comeback appearance against West Brom on Saturday.
"Emile is a player that all the time needs confidence. He has got the confidence of his team-mates and he is a likeable person," said Houllier.
"When he was at Leicester, I recruited him (for Liverpool) so I know what he is capable of.
"Don't forget, he hadn't played for a long time before Saturday (six weeks) because he had this knee operation.
"When you come back from an operation, to bring that sort of performance to the team, is tremendous."
Houllier added: "Is there more to come from Heskey? There is no age to stop you making progress.
"You can progress at any time providing you have got the energy, physical and mental energy.
"He has got both of those, I can tell you. He likes the club, he likes his team-mates, he is a lovable person."
Source: PA
Source: PA